NDA GK Questions 2026

In galvanisation iron or steel is given a coating of zinc, usually by dipping it in the molten metal, and the coating protects the iron in two ways: it keeps out air and moisture, and because zinc is more reactive than iron it corrodes in place of the iron even…

Galena is lead sulphide, the principal ore from which lead is obtained; being a sulphide it is concentrated by froth flotation and then roasted in air to the oxide before reduction.

Silver has the highest electrical conductivity of all metals and also the highest thermal conductivity, but it is costly and tarnishes, so it is used only in specialised contacts and instruments.

Aqua regia is three parts concentrated hydrochloric acid to one part concentrated nitric acid, and the name means royal water, given because the mixture attacks the noble metals gold and platinum, which neither acid can dissolve on its own.

Mercury is the only metal that is liquid at ordinary room temperature, which is why it was long used in thermometers and barometers; it is also the metal that forms amalgams, alloys in which mercury is one component.

Brass takes the workability of copper and the hardness of zinc, resists corrosion and is easy to cast, which is why it is used for utensils, locks, taps, fittings and wind instruments.

Ductility is the property of being drawn into a wire, and gold is the most ductile metal known; it is also the most malleable, so a very small quantity can be beaten into an extremely thin sheet or drawn into a very long wire.

Silver is an element, a pure metal with its own place in the periodic table, so it cannot be an alloy; an alloy is a homogeneous mixture of two or more metals, or of a metal with a non-metal such as carbon.

Calamine is zinc carbonate, and since it is a carbonate ore it is converted to the oxide by calcination, that is by heating in the absence of air, before being reduced to the metal.

The poise is the CGS unit of dynamic or absolute viscosity, named after the French physician Jean Poiseuille, and one poise equals one dyne-second per square centimetre, which is the same as one gram per centimetre per second.

A concave lens is a diverging lens, so for every position of a real object it forms an image that is virtual, erect and diminished.

Indian industry at the New Delhi round was represented by L&T and BEML, who joined officials in the discussion on defence production and logistics.

DAPA is the Republic of Korea's government body responsible for defence acquisition and for overseeing the Korean defence industry, and its Vice Minister Kim Il Dong co-chaired the Joint Committee Meeting in New Delhi alongside Additional Secretary (Defence Production) Dinesh Mahur.

The Joint Committee Meeting between India and the Republic of Korea on defence industries and logistics cooperation reached its tenth edition at the New Delhi round, where the two sides reviewed existing defence ties and discussed ways to widen cooperation in defence production and logistics.

Gyroplanes are small aircraft whose operational capabilities suit short flights and specialised tasks, and carrying passengers over intercontinental distances is well outside what they are described as being fit for.

This is the defining characteristic of the gyroplane: the rotor above the aircraft is not driven by the engine but turns freely in the airflow, and that rotation produces the lift, while the forward thrust is supplied separately by a propeller.

It has issued the Civil Aviation Requirement prescribing the ground and flying training syllabus that a candidate must complete before a pilot licence in the gyroplane category is granted.

The congratulatory message on the relay gold came from the Prime Minister and was put out through the Prime Minister's Office.

The four Indian runners finished ahead of every other team in the final, and the Prime Minister described the result as taking India to the top of the podium, which is the position held only by the gold medallists.

Kiran Pahal, Poovamma MR, Prachi and Vithya Ramraj ran together in that event at the Asian Games and finished first, and the Prime Minister praised their speed and determination for carrying the country to the top of the podium.